Marine propulsion unit



Dec. 25, 1962 c. H. HARRISON 3,070,060

MARINE PROPULSION UNIT Filed Dec. 27, 1960 2 Sheets-Sheet 1 Dec. 25, 1962 c. H. HARRISON v MARINE PROPULSION UNIT 2 Sheets-Sheet 2 Filed Dec. 27, 1960 llite States atent filice 3,070,060 MAQTNE PROPULSEON UNIT Chmles Henry Harrison, Hampton Hill, England, assignor to Woodson Marine Limited, London, England Filed flee. 27, 1960, Ser. No. 78,697 Qlaims priority, application Great Britain Jan. 4, 1960 13 Claims. (Cl. 1155-18} This invention relates to marine propulsion units for use particularly in small cargo carrying boats such as barges and lighters as well as in launches, speedboats, dinghies and like craft, and has for its object the provision of a propulsion unit adapted to permit inboard engine mounting thereof in a variety of craft of different forms of construction in a simple and convenient manner.

A further object of the inventionis to provide an arrangement wherein it is simple to displace the propeller to enable the boat to ride over underwater obstructions or obstacles, e.g. when in use in shallow water.

The invention consists in a marine propulsion unit comprising an internal combustion engine, a propeller and driving means between the engine and the propeller characterised in that the driving means is of inverted-J shape with the propeller at the end of the long limb and the engine at the end of the short limb thereof, and in that support means is provided upon the unit for mounting the engine inboard of the stern of a craft with the propeller submerged and with the driving means positioned over the stern.

The invention further consists in a propulsion unit as set forth in the preceding paragraph in which the support means comprises trunnions on or close to the engine upon which the unit may be pivoted about a horizontal axis below the gunwale of the stern so as to raise the propeller in the water.

The invention still further consists in a propulsion unit as set forth in the preceding paragraph in which the trunnions are pivotally located in a support frame adapted to be fixedly secured in the craft.

Such construction can readily be arranged in barges, lighters, dinghies or like craft with the shorter limb and engine within the craft and the mounting extending over the gunwale thereof so that the propeller is disposed outboard of the craft.

The mounting of the propulsion unit preferably includes trunnions on the short limb thereof, these trunnions being pivotally located in a support frame adapted to be fixedly secured in a craft, so as to provide a substantially horizontal pivotal axis for the unit, so that the latter can swing e.g. against the action of a shock absorber, dashpot or the like, so as, in use, to permit the propeller to ride over obstructions.

The longer limb of the mounting is preferably of tubular form, enclosing a transmission shaft by which the propeller is driven through bevel or like gears, and such transmission shaft is preferably driven from a substantially horizontal drive shaft extending between the long and short limbs.

Such drive shaft may be driven through V belts and pulleys or sprocket wheels and chain, as such arrangement provides for extremely simple removal and replacement of the engine.

The accompanying drawing shows by way of example only one embodiment of the invention in which:

FIGURE 1 is a side elevation of the propulsion unit,

FIGURE 2 is an end elevation of the unit, while FIGURE 3 is a plan view of the unit.

The propulsion unit comprises an internal combustion engine '11 supported in a cradle-like structure comprising side plates 2 and 3 which are U-shaped and which together with the vertical drive casing 4 form an inverted J. These side plates are turned inwards below at 5 and 6 and form attachments for the engine. The connection of the side plates to the vertical casing is such that different lengths of tubing may be provided in the first instance as required to suit craft with different heights of stem.

The side plates 2 and 3 are supported on trunnions 7 and 8 which take their bearings upon the upper ends of the U-shaped support frame 9 adapted to be bolted below to a cross timber such as the timber it or any bearers to suit a particular craft, positioned on the bottom 11 of the craft. The size and position of the bearers are chosen such as will allow the end edges of the plates 2 and 3 to rest upon or just clear the gunwale of the stern 12 of the craft when the drive casing 4 is vertical.

The propulsion unit is pivotal about the common axis of the trunnions 7 and 8 and can be made to assume the position shown by the chain dotted lines 13, by means of a handle, not shown, in which the propeller is lifted clear of the water. The U-shaped support frame 9 is provided with horizontal struts 14 which. are each adjustable as to length, and angle and by which the frame 9 is held rigidly in the craft.

The drive between the engine 1 and the propeller i5 is by way of V belts, not shown, from a V grooved pulley 16 on the crankshaft of the engine to a V grooved pulley 17 on a horizontal shaft 18 journalled in a bearing between the side plates and protruding from the forward, neutral and reversing gear box 19 on the upper end of the vertical drive casing 4 Change of direction is efiected by means of the lever 20.

The side plates and 3 converge towards the rear of the unit and are fastened to the gear box 19 and the vertical casing 4- and also support the fuel tank 21 and silencer 22. Further support for the horizontal shaft 18 is provided by the cross member 23 between the side plates.

The lower end of the vertical casing, which constitutes the longer limb of the inverted-J shape is terminated by a bevel gear housing 24 which provides a journal for the propeller l5 rotatable through the bevel gears by means of a transmission shaft in the vertical housing.

Seeing that the forward, neutral and reverse gearing is used at the top of the vertical housing and not in the water, the lower housing need be only large enough to contain the bevel gearing and thus provide minimum obstruction to its passage through the water.

Between the upper and lower gear housings there is provided a substantially vertical rod 25 having a tiller 26 at the upper end by means of which the rudder 27 may be pivoted about its upper and lower bearings 28 and 29.

A friction or dashpot type of shock absorber or other resilient connection is provided between the unit and its support frame to prevent the return of the former to its operative position too quickly, when required and thus prevent damage to the unit or craft.

As can be seen from the drawing the unit is mounted in a craft by its supporting frame with the engine disposed inboard of the craft with the connecting part of the mounting and the horizontal shaft extending substantially horizontally above the gunwale of the stern, so that the longer limb of the mounting extends downwards outboard of the craft and when the latter is afloat the propeller and rudder are below water lever.

The propulsion unit is operated in substantially conventional manner and constitutes effectively a cross between an inboard arrangement and an outboard mounted engine, since the engine is disposed inboard, but there is no propeller shaft extending through the boat hull, the drive to the propeller passing through a substantially vertical transmission shaft disposed outboard of the craft.

The arrangement is extremely compact and is simple to assemble into a barge or lighter, dinghy or like craft without any need for modification of the craft. The mounting of the engine in a cradle and the provision of a belt drive between the engine and the drive shaft makes it an extremely simple matter to remove the engine, this being done simply by releasing the engine from its mount- -ing and lifting it out of the latter.

The engine can be provided with a self-starter electric motor and for this purpose the pulley wheel on the horizontal drive shaft is made hollow and in the form of the rotor of an electric starter motor containing rotor and stator, and the stator, the electric wiring and connections are upon the support frame and transmission part of the casing of the unit and the engine can be removed with the rotor for maintenance or repair without the need of disconnecting the stator.

ft is also within the scope of the invention to arrange for the vertically positioned tubular casing 4 to be rotatable about its longitudinal axis for the purpose of steering and possibly reversing.

A standard mounting can be provided for a variety of sizes of engine, and the drive ratio of the propeller according to the size of the engine can be provided for simply by use of appropriately sized pulleys.

A further advantage of the invention resides in the fact that the whole propulsion unit can be removed from the craft by releasing the supporting frame.

It is to be understood that the above description is by way of example only and that details for carrying the invention into effect may be varied without departing from the scope of the invention claimed.

I claim:

1. A marine propulsion unit comprising an internal combustion engine, a propeller, driving means connected between said engine and propeller, said driving means being of an inverted J shape with the propeller mounted at the end of the long limb of the inverted J-shaped driving means for submersion in water, and with the engine mounted at the end of the short limb thereof in a manner to project below and inboard of the gunwale of the stern of a marine craft, support means for attachment to the stern of a marine craft, said support means com prising trunnions pivotally connecting said engine to said support means below and inboard of the gunwale of the stern of a marine craft, and said engine being disposed closely adjacent said trunnions whereby said engine may pivot about an axis below and inboard of the gunwale of a marine craft to raise the connecting propeller upward out of the water.

2. 'A marine propulsion unit according to claim 1, in which said support means further comprises a support frame adapted to be fixedly mounted within a marine craft adjacent the stern thereof, and said trunnions are pivotally mounted to said support means.

3. Marine propulsion unit as claimed in claim 1 in which the trunnions are pivotally located in a support frame adapted to be fixedly secured in the craft.

4. Marine propulsion unit as claimed in claim 1 in which a shock absorber is provided between the unit and a support frame to allow free movement of the propeller when raised and controlled movement when lowered in the water.

5. Marine propulsion unit as claimed in claim 1 in which the trunnions are positioned forward of the centre of gravity of the unit in order that the propeller shall be urged to remain submerged under the action of gravity.

6. Marine propulsion unit as claimed in claim 1 in which the long limb of the .J is a normally vertically positioned tubular casing enclosing a transmission shaft by which the propeller is driven by way of bevel gears, while the horizontal part of the J comprises a casing enclosing 'a reversing gear and a horizontal drive shaft.

7. Marine propulsion unit as claimed in claim 6 in which the horizontal drive shaft is provided with a V grooved pulley or toothed sprocket wheel and the short limb includes a belt or chain drive between the engine and the pulley or wheel.

8. Marine propulsion unit-as claimed in claim 6 in which the engine is removably mounted in a cradle attached to'the said casings.

9. Marine propulsion unit as claimed in claim 7 in which the V grooved pulley is hollow and contains an electric starter motor.

10. Marine propulsion unit as claimed in claim 1 provided with a pair of adjustable horizontal struts upon the support means adapted to be secured to the stern of a craft.

11. Marine propulson unit as claimed in claim 6 in which the vertically positioned tubular casing is rotatable about its longitudinal axis to steer the craft.

12. A marine propulsion unit comprising an internal combusion engine, a propeller, driving means connecting said engine to said propeller, said driving means being of an inverted J shape with the propeller mounted at theend of the long limb of the inverted J-shaped driving means for submersion in Water, with the inverted J-shaped driving means adapted to be positioned with the roof of the J astride the gunwale, and with the engine mounted to the end of the short limb of the inverted J-shaped driving means in a manner to project below the gunwale of the stern of a marine craft and within the marine craft, and supporting means for mounting said unit to the stern of a marine craft.

13. A marine propulsion unit comprising an internal combustion engine, a propeller, driving means connecting said engine to said propeller, said driving means being of an inverted J shape with the propeller mounted at the end of the long limb of the inverted J-shaped driving means for submersion in the water, and with the engine mounted at the end of the short limb thereof, support means for said unit, and trunnion means pivotally connecting said engine to said support means, said support means being adapted to be attached to the stern of a marine craft with the trunnion means being disposed below and to the gunwale of a craft and within the said craft to provide a horizontal axis for pivoting said unit about said trunnion means at an axis below the gunwale for raising and lowering the propeller in and out of the water.

References Cited in the file of this patent UNITED STATES PATENTS 1,482,196 Ketring Jan. 29, 1924 2,217,903 Groves Oct. 15, 1940 2,722,193 Brindley Nov. 1, 1955 FOREIGN PATENTS 115,842 Germany June 28, 1899 

